U.S. patent number 5,031,411 [Application Number 07/514,528] was granted by the patent office on 1991-07-16 for efficient dehumidification system.
This patent grant is currently assigned to DEC International, Inc.. Invention is credited to Kenneth C. Gehring, Phillip R. Steinmetz, Joel C. Zabel.
United States Patent |
5,031,411 |
Gehring , et al. |
July 16, 1991 |
Efficient dehumidification system
Abstract
Efficient dehumidification is provided by directing air flow
through a coil (30, 60) to cool the air below the dew point such
that water vapor in the air is condensed to liquid to dehumidify
the air, and then directing air flow through the coil to heat the
air to a temperature below the incoming air to the coil and above
the dew point of the air. Air flow is directed along a first set of
coil sections (42, 64) giving up heat to refrigerant in the first
set of coil sections to evaporate refrigerant in the first set of
coil sections, and then directing the air flow along a second set
of coil sections (44, 66) absorbing heat from refrigerant in the
second set of coil sections to condense refrigerant in the second
set of coil sections. The coil sections are connected to
alternately evaporate and condense refrigerant in the coil
differentially such that less refrigerant is condensed in
condensing coil sections than is evaporated in evaporating coil
sections. Heat is transferred from air flow along a first air flow
path leg (48, 72) through the evaporating coil sections (42, 64) to
air flow along a second air flow path leg (50, 74) through the
condensing coil sections (44, 66) through the media of the
refrigerant, to put heat back into the air flow along the second
air flow path leg from the first air flow path leg, reducing the
net cooling effect of the coil, to reduce the net load on the
compressor by the coil such that the compressor will consume power
based on the net cooling load, while the coil provides the greater
cooling capacity of the evaporating coil sections (42, 64), which
allows more moisture to be condensed from the air with less
energy.
Inventors: |
Gehring; Kenneth C. (Cottage
Grove, WI), Zabel; Joel C. (Madison, WI), Steinmetz;
Phillip R. (Madison, WI) |
Assignee: |
DEC International, Inc.
(Madison, WI)
|
Family
ID: |
24047580 |
Appl.
No.: |
07/514,528 |
Filed: |
April 26, 1990 |
Current U.S.
Class: |
62/93; 62/526;
62/525 |
Current CPC
Class: |
F24F
3/153 (20130101); F25B 39/02 (20130101); F24F
3/1405 (20130101); F25B 5/04 (20130101) |
Current International
Class: |
F24F
3/14 (20060101); F24F 3/12 (20060101); F25B
5/04 (20060101); F25B 39/02 (20060101); F25B
5/00 (20060101); F25D 017/06 () |
Field of
Search: |
;62/524,525,526,93,272,277 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
0311086 |
|
Dec 1988 |
|
JP |
|
0311087 |
|
Dec 1988 |
|
JP |
|
Primary Examiner: Makay; Albert J.
Assistant Examiner: Sollecito; John
Attorney, Agent or Firm: Andrus, Sceales, Starke &
Sawall
Claims
We claim:
1. A method for efficiently dehumidifying air comprising:
providing a compressor for delivering hot compressed
refrigerant;
providing a condenser receiving refrigerant from said compressor
and condensing same;
providing an expansion device receiving refrigerant from said
condenser and expanding same;
providing a coil having an inlet receiving refrigerant from said
expansion device and having an outlet delivering refrigerant to
said compressor;
circulating refrigerant from said compressor to said condenser to
said expansion device to said coil and back to said compressor in a
refrigeration cycle;
directing air flow through said coil to cool the air below its dew
point such that water vapor in the air is condensed to liquid to
dehumidify the air, and then directing air flow through the coil to
heat the air to a temperature below the incoming air to the coil
and above the dew point of the air, such that the coil presents a
net cooling load on the compressor represented by the enthalpy
difference in air entering and leaving the coil, such that the air
entering the coil is cooled below the dew point and then reheated
before leaving the coil, such that the air leaving the coil has a
lower temperature than the air entering the coil, and such that the
air leaving the coil is dehumidified relative to the air entering
the coil.
2. A method for efficiently dehumidifying air comprising:
providing a compressor for delivering hot compressed
refrigerant;
providing a condenser receiving refrigerant from said compressor
and condensing same;
providing an expansion device receiving refrigerant from said
condenser and expanding same;
providing a coil having an inlet receiving refrigerant from said
expansion device and having an outlet delivering refrigerant to
said compressor;
circulating refrigerant from said compressor to said condenser to
said expansion device to said coil and back to said compressor in a
refrigeration cycle;
directing air flow along a first set of coil sections and giving up
heat to refrigerant in said first set of coil sections to evaporate
refrigerant in said first set of coil sections, and then directing
said air flow along a second set of coil sections absorbing heat
from refrigerant in said second set of coil sections to condense
refrigerant in said second set of coil sections.
3. The invention according to claim 2 wherein said outlet of said
coil has a lower temperature than said inlet of said coil.
4. A method for efficiently dehumidifying air comprising:
providing a compressor for delivering hot compressed
refrigerant;
providing a condenser receiving refrigerant from said compressor
and condensing same;
providing an expansion device receiving refrigerant from said
condenser and expanding same;
providing a coil having an inlet receiving refrigerant from said
expansion device and having an outlet delivering refrigerant to
said compressor;
circulating refrigerant from said compressor to said condenser to
said expansion device to said coil and back to said compressor in a
refrigeration cycle;
alternately evaporating and condensing refrigerant in said
coil;
directing air flow along evaporating sections of said coil and then
along condensing sections of said coil.
5. The invention according to claim 4 comprising differentially
evaporating and condensing refrigerant in said coil such that less
refrigerant is condensed in the condensing coil sections than is
evaporated in the evaporating coil sections, such that said coil
outlet has a higher percentage gas refrigerant than said coil
inlet, and such that said coil outlet has a lower percentage liquid
refrigerant than said coil inlet, and such that said coil outlet
has a lower temperature than said coil inlet.
6. A method for efficiently dehumidifying air comprising:
providing a compressor for delivering hot compressed
refrigerant;
providing a condenser receiving refrigerant from said compressor
and condensing same;
providing an expansion device receiving refrigerant from said
condenser and expanding same;
providing a coil having a plurality of serially connected coil
sections comprising first and second sets;
circulating refrigerant from said compressor to said condenser to
said expansion device to said coil and back to said compressor in a
refrigeration cycle, said coil having an inlet receiving
refrigerant from said expansion device and having an outlet
delivering refrigerant to said compressor, said outlet of said coil
being of lower temperature than said inlet of said coil;
circulating refrigerant through said serially connected coil
sections by circulating refrigerant through the first coil section
of said first set, then through the first coil section of said
second set, then through the second coil section of said first set,
then through the second coil section of said second set, and so
on;
directing air flow in a path having first and second legs extending
along said coil, by
directing air flow along said first leg of said path along said
first set of coil sections,
and then directing air flow along said second leg of said path
along said second set of coil sections;
transferring heat from air flowing along said first leg of said
path to refrigerant in said first set of coil sections such that
said refrigerant absorbs heat from the air and evaporates to lower
the temperature of the air below its dew point such that water
vapor in the air is condensed to liquid to dehumidify the air;
circulating refrigerant from said first set of coil sections to
said second set of coil sections by circulating refrigerant from a
coil section of said first set to the next serially connected
respective coil section of said second set;
transferring heat from said refrigerant in said second set of coil
sections to air flowing along said second leg of said path such
that heat is given up to the air and the refrigerant condenses, to
raise the temperature of the air such that dehumidified and warmed
air flows from said second leg of said path,
such that heat is transferred from air flow along said first leg of
said path to air flow along said second leg of said path through
the media of said refrigerant, to put heat back into the air flow
along said second leg of said path from the air flow along said
first leg of said path, reducing the net cooling effect of said
coil, to reduce the net load on said compressor by said coil such
that said compressor will consume power based on the net cooling
load while said coil provides the greater cooling capacity of said
first set of coil sections, which allows more moisture to be
condensed from the air with less energy.
7. The invention according to claim 6 comprising:
directing air flow along said first leg of said path by directing
air flow across said first coil section of said first set, then
across said second coil section of said first set, and so on until
air flow crosses the last coil section of said first set;
then directing air flow along said second leg of said path by
directing air flow across the last coil section of said second set,
and then across the next to last coil section of said second set,
and so on until air flow crosses said first coil section of said
second set,
such that air flow along said path is initially directed across
said first coil section of said first set, and is lastly directed
across said first coil section of said second set.
8. The invention according to claim 7 wherein said coil inlet is
said first coil section of said first set.
9. The invention according to claim 8 wherein said coil outlet is
said last coil section of said second set.
10. The invention according to claim 8 wherein said coil outlet is
said last coil section of said first set.
11. A method for efficiently dehumidifying air comprising:
providing a compressor for delivering hot compressed
refrigerant;
providing a condenser receiving refrigerant from said compressor
and condensing same;
providing an expansion device receiving refrigerant from said
condenser and expanding same;
providing a coil having an inlet receiving refrigerant from said
expansion device and having an outlet delivering refrigerant to
said compressor;
circulating refrigerant from said compressor to said condenser to
said expansion device to said coil and back to said compressor in a
refrigeration cycle, said coil outlet being of lower temperature
than said coil inlet;
directing air flow in a straight-through path having first and
second legs extending along said coil,
directing air flow along said first leg of said path along a first
portion of said coil toward said coil outlet to lower the
temperature of the air below its dew point such that water vapor in
the air is condensed to liquid to dehumidify the air,
then directing air flow along said second leg of said path along a
second portion of said coil away from said coil outlet to raise the
temperature of the air such that dehumidified and warmed air flows
from said second leg of said path at said second portion of said
coil;
transferring heat from air flowing along said first leg of said
path to refrigerant in said first portion of said coil;
circulating refrigerant from said first portion of said coil to
said second portion of said coil;
transferring heat from said refrigerant in said second portion of
said coil to air flowing along said second leg of said path, such
that heat is transferred from air flow along said first leg of said
path to air flow along said second leg of said path through the
media of said refrigerant, to put heat back into the air flow along
said second leg of said path from the air flow along said first leg
of said path, reducing the net cooling effect of said coil, to
reduce the net load on said compressor by said coil such that said
compressor will consume power based on the net cooling load, while
said coil provides the greater cooling capacity of said first
portion, which allows more moisture to be condensed from the air
with less energy.
12. The invention according to claim 11 comprising:
circulating refrigerant through said coil in a path having multiple
parallel runs interconnected at their ends such that the outermost
run on one side of the coil is connected to the outermost run on
the other side of the coil, and the next to outermost run on the
one side of the coil is connected to the next to outermost run on
the other side of the coil, and so on, one of said outermost runs
providing said coil inlet, a central run providing said coil
outlet;
directing air flow along said first leg of said path along said
first portion of said coil from one of said outermost runs to said
central run;
directing air flow along said second leg of said path along said
second portion of said coil from said central run to the other of
said outermost runs.
13. The invention according to claim 12 comprising directing air
flow along said first and second legs rectilinearly aligned with
each other and perpendicular to said runs.
14. The invention according to claim 13 comprising providing a
plurality of further expansion devices in said coil along the
length thereof between said coil inlet and said coil outlet
progressively expanding the refrigerant and progressively reducing
refrigerant temperature.
15. The invention according to claim 11 comprising directing said
dehumidified and warmed air from said second leg of said path at
said second portion of said coil through said condenser.
16. A method for efficiently dehumidifying air comprising:
providing a compressor for delivering hot compressed
refrigerant;
providing a condenser receiving refrigerant from said compressor
and condensing same;
providing an expansion device receiving refrigerant from said
condenser and expanding same;
providing a coil having an inlet receiving refrigerant from said
expansion device and having an outlet delivering refrigerant to
said compressor;
circulating refrigerant from said compressor to said condenser to
said expansion device to said coil and back to said compressor in a
refrigeration cycle, said coil outlet being of lower temperature
than said coil inlet;
directing air flow in a loop-back path having first and second legs
extending along said coil, by
directing air flow along said first leg of said path along a first
portion of said coil in a first direction from said coil inlet
toward said coil outlet to lower the temperature of the air below
its dew point such that water vapor in the air is condensed to
liquid to dehumidify the air,
then reversing the air flow from said first direction at said coil
outlet,
then directing the air flow along said second leg of said path
along a second portion of said coil in a second direction from said
coil outlet toward said coil inlet to raise the temperature of the
air such that dehumidified and warmed air flows from said second
leg of said path at said second portion of said coil;
transferring heat from air flowing along said first leg of said
path to refrigerant in said first portion of said coil;
circulating refrigerant from said first portion of said coil to
said second portion of said coil;
transferring heat from said refrigerant in said second portion of
said coil to air flowing along said second leg of said path, such
that heat is transferred from air flow along said first leg of said
path to air flow along said second leg of said path through the
media of said refrigerant, to put heat back into the air flow along
said second leg of said path from the air flow along said first leg
of said path, reducing the net cooling effect of said coil, to
reduce the net load on said compressor by said coil such that said
compressor will consume power based on the net cooling load, while
said coil provides the greater cooling capacity of said first
portion, which allows more moisture to be condensed from the air
with less energy.
17. The invention according to claim 16 comprising:
circulating said refrigerant through said coil in a serpentine path
having multiple straight runs and having at the end of each run a
reverse bend leading the to next run;
directing air flow along said first leg of said path along a first
portion of each said run in said first direction;
directing air flow along said second leg of said path along a
second portion of each said run in a second direction.
18. The invention according to claim 17 comprising reversing air
flow at said coil outlet by directing air flow along a U-shape bend
from said first direction to said second direction, and wherein
said air flow path, including said first and second legs and said
U-shape bend, and each said run of said coil are all coplanar.
19. The invention according to claim 18 comprising directing air
flow along said first and second legs parallel to each other and
perpendicular to each of said runs.
20. The invention according to claim 19 comprising providing a
plurality of expansion devices in said coil along the length of
said serpentine path progressively expanding the refrigerant and
progressively reducing refrigerant temperature.
21. The invention according to claim 16 comprising directing said
dehumidified and warmed air from said second leg of said path at
said second portion of said coil through said condenser.
22. A method for air conditioning and efficiently dehumidifying an
enclosed space, comprising:
providing a compressor for delivering hot compressed
refrigerant;
providing a condenser receiving refrigerant from said compressor
and condensing same;
providing an expansion device receiving refrigerant from said
condenser and expanding same;
providing a coil having an inlet receiving refrigerant from said
expansion device and having an outlet delivering refrigerant to
said compressor;
circulating refrigerant from said compressor to said condenser to
said expansion device to said coil and back to said compressor in a
refrigeration cycle, said condenser being exterior to said space
and exhausting heat given up by said refrigerant during condensing
thereof, said coil being within said space for cooling said space,
said coil outlet being of lower temperature than said coil
inlet;
directing air flow along said coil to cool said space by directing
air flow in a path having first and second legs extending along
said coil, by
directing air flow along said first leg of said path along a first
portion of said coil from said coil inlet toward said coil outlet
to lower the temperature of the air below its dew point such that
water vapor in the air is condensed to liquid to dehumidify the
air,
then directing the air flow along said second leg of said path
along a second portion of said coil from said coil outlet toward
said coil inlet such that dehumidified air flows from said second
leg of said path at said second portion of said coil at a
temperature greater than the temperature of the air at said coil
outlet and less than the temperature of air exterior to said
space;
transferring heat from air flowing along said first leg of said
path to refrigerant in said first portion of said coil;
circulating refrigerant from said first portion of said coil to
said second portion of said coil;
transferring heat from said refrigerant in said second portion of
said coil to air flowing along said second leg of said path, such
that heat is transferred from air flow along said first leg of said
path to air flow along said second leg of said path through the
media of said refrigerant, to put heat back into the air flow along
said second leg of said path from the air flow along said first leg
of said path, reducing the net cooling effect of said coil, to
reduce the net load on said compressor by said coil such that said
compressor will consume power based on the net cooling load, while
said coil provides the greater cooling capacity of said first
portion, which allows more moisture to be condensed from the air
with less energy.
23. A dehumidifier comprising:
a compressor for delivering hot compressed refrigerant;
a condenser receiving refrigerant from said compressor and
condensing same;
an expansion device receiving refrigerant from said condenser and
expanding same;
a coil having an inlet receiving refrigerant from said expansion
device and having an outlet delivering refrigerant to said
compressor, said refrigerant being circulated from said compressor
to said condenser to said expansion device to said coil and back to
said compressor in a refrigeration cycle, said coil outlet being of
lower temperature than said coil inlet;
means directing air flow through said coil to cool the air below
its dew point such that water vapor in the air is condensed to
liquid to dehumidify the air, said air flow then being directed
through the coil to heat the air to a temperature below the
incoming air to the coil and above the dew point of the air, such
that the coil presents a net cooling load on the compressor
represented by the enthalpy difference in air entering and leaving
the coil, such that the air entering the coil is cooled down below
the dew point and then reheated before leaving the coil, such that
the air leaving the coil has a lower temperature than the air
entering the coil, and such that the air leaving the coil is
dehumidified relative to the air entering the coil.
24. A dehumidifier comprising:
a compressor for delivering hot compressed refrigerant;
a condenser receiving refrigerant from said compressor and
condensing same;
an expansion device receiving refrigerant from said condenser and
expanding same;
a coil having an inlet receiving refrigerant from said expansion
device and having an outlet delivering refrigerant to said
compressor, said refrigerant being circulated from said compressor
to said condenser to said expansion device to said coil and back to
said compressor in a refrigeration cycle, said coil outlet being of
lower temperature than said coil inlet, said coil having a first
set of sections for evaporating refrigerant and a second set of
sections for condensing refrigerant;
means directing air flow along said first set of coil sections and
giving up heat to refrigerant in said first set of coil sections to
evaporate refrigerant in said first set of coil sections, and then
directing said air flow along said second set of coil sections
absorbing heat from refrigerant in said second set of coil sections
to condense refrigerant in said second set of coil sections.
25. The invention according to claim 24 wherein said coil outlet
has a lower temperature than said coil inlet.
26. A dehumidifier comprising:
a compressor for delivering hot compressed refrigerant;
a condenser receiving refrigerant from said compressor and
condensing same;
an expansion device receiving refrigerant from said condenser and
expanding same;
a coil having an inlet receiving refrigerant from said expansion
device and having an outlet delivering refrigerant to said
compressor, said refrigerant being circulated from said compressor
to said condenser to said expansion device to said coil and back to
said compressor in a refrigeration cycle, said refrigerant being
alternately evaporated and condensed in said coil;
means directing air flow along evaporating sections of said coil
and then along condensing sections of said coil.
27. The invention according to claim 26 wherein said refrigerant is
differentially evaporated and condensed in said coil such that less
refrigerant is condensed in the condensing coil sections than is
evaporated in the evaporating coil sections, such that said coil
outlet has a higher percentage gas refrigerant than said coil
inlet, and such that said coil outlet has a lower percentage liquid
refrigerant than said coil inlet, and such that said coil outlet
has a lower temperature than said coil inlet.
28. A dehumidifier comprising:
a compressor for delivering hot compressed refrigerant;
a condenser receiving refrigerant from said compressor and
condensing same;
an expansion device receiving refrigerant from said condenser and
expanding same;
a coil having an inlet receiving refrigerant from said expansion
device and having an outlet delivering refrigerant to said
compressor, said refrigerant being circulated from said compressor
to said condenser to said expansion device to said coil and back to
said compressor in a refrigeration cycle, said coil outlet being of
lower temperature than said coil inlet, said coil having a
plurality of serially connected coil sections comprising first and
second sets, said refrigerant being circulated through said
serially connected coil sections, said refrigerant being initially
circulated through the first coil section of said first set, then
through the first coil section of said second set, then through the
second coil section of said first set, then through the second coil
section of said second set, and so on;
means directing air flow in a path having first and second legs
extending along said coil, comprising
means directing air flow along said first leg of said path along
said first set of coil sections,
means then directing the air flow along said second leg of said
path along said second set of coil sections,
heat from air flowing along said first leg of said path being
transferred to refrigerant in said first set of coil sections such
that said refrigerant absorbs heat from the air and evaporates to
lower the temperature of the air below the dew point such that
water vapor in the air is condensed to liquid to dehumidify the
air, said refrigerant being circulated from said first set of coil
sections to said second set of coil sections by circulation of
refrigerant from a coil section of said first set to the next
serially connected respective coil section of said second set, heat
from said refrigerant in said second set of coil sections being
transferred to air flowing along said second leg of said path such
that heat is given up to the air and the refrigerant condenses, to
raise the temperature of the air such that dehumidified and warmed
air flows from said second leg of said path, such that heat is
transferred from air flow along said first leg of said path to air
flow along said second leg of said path through the media of said
refrigerant, to put heat back into the air flow along said second
leg of said path from the air flow along said first leg of said
path, reducing the net cooling effect of said coil, to reduce the
net load on said compressor by said coil such that said compressor
will consume power based on the net cooling load, while the coil
provides the greater cooling capacity of said first set of coil
sections, which allows more moisture to be condensed from the air
with less energy.
29. The invention according to claim 28 wherein said coil inlet is
said first coil section of one of said first and second sets.
30. The invention according to claim 28 wherein:
said means directing air flow along said first leg of said path
directs air flow across said first coil section of said first set,
then across said second coil section of said first set, and so on
until said air flow crosses the last coil section of said first
set;
said means directing air flow along said second leg of said path
directs air flow across the last coil section of said second set,
then across the next to last coil section of said second set, and
so on until said air flow crosses said first coil section of said
second set,
such that air flow along said path is initially directed across
said first coil of said first set, and is lastly directed across
said first coil of said second set.
31. The invention according to claim 30 wherein said coil inlet is
said first coil section of said first set.
32. The invention according to claim 31 wherein said coil outlet is
said last coil section of said second set.
33. The invention according to claim 31 wherein said coil outlet is
said last coil section of said first set.
34. A dehumidifier comprising:
a compressor for delivering hot compressed refrigerant;
a condenser receiving refrigerant from said compressor and
condensing same;
an expansion device receiving refrigerant from said condenser and
expanding same;
a coil having an inlet receiving refrigerant from said expansion
device and having an outlet delivering refrigerant to said
compressor, said refrigerant being circulated from said compressor
to said condenser to said expansion device to said coil and back to
said compressor in a refrigeration cycle, said coil outlet being of
lower temperature than said coil inlet;
means directing air flow in a straight-through path having first
and second legs extending along said coil, comprising
means directing air flow along said first leg of said path along a
first portion of said coil from said coil inlet toward said coil
outlet to lower the temperature of the air below the dew point such
that water vapor in the air is condensed to liquid to dehumidify
the air,
means then directing the air flow along said second leg of said
path along a second portion of said coil from said coil outlet
toward said coil inlet to raise the temperature of the air such
that dehumidified and warmed air flows from said second leg of said
path at said second portion of said coil,
wherein heat is transferred from air flowing along said first leg
of said path to refrigerant in said first portion of said coil, and
refrigerant is circulated from said first portion of said coil to
said second portion of said coil, and heat is transferred from said
refrigerant in said second portion of said coil to air flowing
along said second leg of said path, such that heat is transferred
from air flow along said first leg of said path to air flow along
said second leg of said path through the media of said refrigerant,
to put heat back into the air flow along said second leg of said
path from the air flow along said first leg of said path, reducing
the net cooling effect of said coil, to reduce the net load on said
compressor by said coil such that said compressor will consume
power based on the net cooling load, while said coil provides the
greater cooling capacity of said first portion, which allows more
moisture to be condensed from the air with less energy.
35. The invention according to claim 34 wherein said coil has
multiple parallel runs interconnected at their ends such that the
outermost run on one side of the coil is connected to the outermost
run on the other side of the coil, and the next to outermost run on
the one side of the coil is connected to the next to outermost run
on the other side of the coil, and so on, one of said outermost
runs being said coil inlet, a central run being said coil outlet,
and wherein said means directing air flow directs air flow along
said first leg of said path along said first portion of said coil
from one of said outermost runs on to said central run, and wherein
said means directing air flow directs air flow along said second
leg of said path along said second portion of said coil from said
central run to the other of said outermost runs.
36. The invention according to claim 35 wherein said first and
second legs are perpendicular to said runs.
37. The invention according to claim 36 wherein said first and
second legs are rectilinearly aligned with each other.
38. The invention according to claim 36 comprising a plurality of
further expansion devices in said coil along the length thereof
between said coil inlet and said coil outlet progressively
expanding the refrigerant and progressively reducing refrigerant
temperature.
39. The invention according to claim 34 wherein said dehumidified
and warmed air is directed from said second leg of said path at
said second portion of said coil through said condenser.
40. A dehumidifier comprising:
a compressor for delivering hot compressed refrigerant;
a condenser receiving refrigerant from said compressor and
condensing same;
an expansion device receiving refrigerant from said condenser and
expanding same;
a coil having an inlet receiving refrigerant from said expansion
device and having an outlet delivering refrigerant to said
compressor, said refrigerant being circulated from said compressor
to said condenser to said expansion device to said coil and back to
said compressor in a refrigeration cycle, said coil outlet being of
lower temperature than said coil inlet;
means directing air flow in a loop-back path having first and
second legs extending along said coil, comprising
means directing air flow along said first leg of said path along a
first portion of said coil in a first direction from said coil
inlet toward said coil outlet to lower the temperature of the air
below the dew point such that water vapor in the air is condensed
to liquid to dehumidify the air,
means then reversing said air flow from said first direction at
said coil outlet,
means then directing said air flow along said second leg of said
path along a second portion of said coil in a second direction from
said coil outlet toward said coil inlet to raise the temperature of
the air such that dehumidified and warmed air flows from said
second leg of said path at said second portion of said coil,
wherein heat is transferred from air flowing along said first leg
of said path to refrigerant in said first portion of said coil, and
refrigerant is circulated from said first portion of said coil to
said second portion of said coil, and heat is transferred from said
refrigerant in said second portion of said coil to air flowing
along said second leg of said path, such that heat is transferred
from air flow along said first leg of said path to air flow along
said second leg of said path through the media of said refrigerant,
to put heat back into the air flow along said second leg of said
path from the air flow along said first leg of said path, reducing
the net cooling effect of said coil, to reduce the net load on said
compressor by said coil such that said compressor will consume
power based on the net cooling load, while said soil provides the
greater cooling capacity of said first portion, which allows more
moisture to be condensed from the air with less energy.
41. The invention according to claim 40 wherein said coil has
multiple parallel runs and has at the end of each run a reverse
bend leading to the next run to form a serpentine path, and wherein
air flow is directed along said first leg of said path along a
first portion of each said run in said first direction, and wherein
air flow is directed along said second leg of said path along a
second portion of each said run in said second direction.
42. The invention according to claim 41 wherein air flow is
reversed at said coil outlet by a U-shape bend between said first
and second directions, and wherein said air flow path, including
said first and second legs and said U-shape bend, and each said run
of said coil are all coplanar.
43. The invention according to claim 42 wherein said first and
second legs of said air flow path are parallel to each other and
perpendicular to each of said runs.
44. The invention according to claim 43 comprising a plurality of
further expansion devices in said coil along the length of said
serpentine path progressively expanding the refrigerant and
progressively reducing refrigerant temperature.
45. The invention according to claim 40 wherein dehumidified and
warmed air is directed from said second leg of said path at said
second portion of said coil through said condenser.
46. An air conditioner and dehumidifier for an enclosed space,
comprising:
a compressor for delivering hot compressed refrigerant;
a condenser receiving refrigerant from said compressor and
condensing same, said condenser being exterior to said space and
exhausting heat given up by said refrigerant during condensing
thereof;
an expansion device receiving refrigerant from said condenser and
expanding same;
a coil having an inlet receiving refrigerant from said expansion
device and having an outlet delivering refrigerant to said
compressor, said refrigerant being circulated from said compressor
to said condenser to said expansion device to said coil and back to
said compressor in a refrigeration cycle, said coil being within
said space for cooling said space, said coil outlet being of lower
temperature than said coil inlet;
means directing air flow along said coil to cool said space
including means directing air flow in a path having first and
second legs extending along said evaporator, comprising
means directing air flow along said first leg of said path along a
first portion of said coil toward said coil outlet to lower the
temperature of the air below the dew point such that water vapor in
the air is condensed to liquid to dehumidify the air,
means then directing said air flow along said second leg cf said
path along a second portion of said coil away from said coil outlet
such that dehumidified air flows from said second leg of said path
at said second portion of said coil at a temperature greater than
the temperature of the air at said coil outlet and less than the
temperature of air exterior to said space,
wherein heat is transferred from air flowing along said first leg
of said path to refrigerant in said first portion of said coil, and
refrigerant is circulated from said first portion of said coil to
said second portion of said coil, and heat is transferred from said
refrigerant in said second portion of said coil to air flowing
along said second leg of said path, such that heat is transferred
from air flow along said first leg of said path to air flow along
said second leg of said path through the media of said refrigerant,
to put heat back into the air flow along said second leg of said
path from the air flow along said first leg of said path, reducing
the net cooling effect of said coil, to reduce the net load on said
compressor by said coil such that said compressor will consume
power based on the net cooling load, while said coil provides the
greater cooling capacity of said first portion, which allows more
moisture to be condensed from the air with less energy.
Description
BACKGROUND AND SUMMARY
The invention relates to dehumidifier systems, and more
particularly to methods and apparatus for improved efficiency.
Dehumidifier systems are known in the prior art. A compressor
delivers hot compressed refrigerant gas. A condenser receives the
refrigerant gas and condenses same to hot refrigerant liquid. An
expansion device receives the refrigerant liquid from the condenser
and expands same to drop the temperature and pressure of the
liquid. An evaporator receives the cool liquid refrigerant from the
expansion device and evaporates same to cold gas refrigerant, which
is returned to the compressor to complete the refrigeration cycle.
Air flow is directed across the evaporator to cool the air below
the dew point such that water vapor in the air is condensed to
liquid to dehumidify the air. The dehumidified air is then directed
across the condenser to warm the air. A typical prior art
dehumidifier will yield about 2 to 3.5 pints of water from the air
per kilowatt hour of electricity used by the compressor.
The present invention yields about 5 pints of water from the air
per kilowatt hour of electricity used by the compressor, providing
a significant increase in efficiency. This is accomplished in the
present invention by reducing the net cooling effect of an
evaporator coil, to reduce the net load on the compressor such that
the compressor will consume power based on the net cooling load,
while providing the coil with some sections of greater cooling
capacity, which allows more moisture to be condensed from the air
with less energy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a dehumidifier known in the prior art.
FIG. 2 shows a dehumidifier in accordance with the present
invention.
FIG. 3 shows an alternate embodiment of a dehumidifier in
accordance with the present invention.
FIG. 4 shows an air conditioner known in the prior art.
FIG. 5 shows an air conditioner in accordance with the present
invention.
FIG. 6 shows an alternate embodiment of an air conditioner in
accordance with the present invention.
FIG. 7 is a pressure-enthalpy diagram and shows a refrigeration
cycle as known in the prior art.
FIG. 8 is a pressure-enthalpy diagram and shows a refrigeration
cycle in accordance with the present invention.
FIG. 9 is an enlarged portion of FIG. 8.
FIG. 10 is like FIG. 9 and shows a further embodiment.
FIG. 11 is like FIG. 10 and shows a further embodiment.
DETAILED DESCRIPTION
FIG. 1 shows a dehumidifier 10 known in the prior art. A compressor
12 delivers compressed hot gas refrigerant. A condenser 14 receives
the hot gas refrigerant and condenses same to hot liquid
refrigerant, and gives up heat to the air flow therethrough. An
expansion device 16 receives the hot liquid refrigerant and expands
same to a liquid and gas refrigerant mixture of reduced temperature
and pressure. Expansion device 16 is typically a flow restrictor,
capillary tube, or other pressure reducer. An evaporator 18
receives the cool liquid and gas refrigerant mixture and evaporates
the liquid portion to cool gas refrigerant, and absorbs heat from
the air flow therethrough. The refrigerant is circulated from
compressor 12 to condenser 14 to expansion device 16 to evaporator
18 and back to compressor 12 in a refrigeration cycle. Air flow,
typically driven by a fan (not shown), is directed by a duct or
housing 19 along a path through evaporator 18 and condenser 14. As
the air flows through evaporator 18 from point 20 to point 22, the
temperature of the air drops below the dew point such that water
vapor in the air is condensed to liquid to dehumidify the air. The
air is heated as it flows through condenser 14 from point 22 to
point 24, and the warmed and dehumidified air is discharged to the
desired space, such as a basement, or other interior space of a
house or building.
FIG. 2 shows a dehumidifier 18 in accordance with the present
invention, and uses like reference numerals from FIG. 1 where
appropriate to facilitate understanding. A coil 30 has a plurality
of serially connected coil sections 31 through 40 comprising first
and second sets 42 and 44. Coil section 31 is the coil inlet and
receives refrigerant from expansion device 16. Coil section 36 is
the coil outlet and delivers refrigerant to compressor 12. Coil
outlet 36 is of lower temperature than coil inlet 31. The
refrigerant is circulated through the serially connected coil
sections by circulating refrigerant through the first coil section
31 of the first set 42, then through the first coil section 40 of
the second set 44, then through the second coil section 32 of the
first set 42, then through the second coil section 39 of the second
set 44, then through the third coil section 33 of the first set 42,
then through the third coil section 38 of the second set 44, and so
on. The temperature and pressure of the refrigerant as it passes
through coil 30 from inlet 31 to outlet 36 is reduced by the size
of the tubing used for coil sections 31-40 and/or by restrictions
between the coil sections, such as reduced interconnecting tubing
as at 46.
Air flow from point 20 to point 22 is directed by duct 47 along a
path having first and second legs 48 and 50 extending along coil
30. Air flow is directed along the first leg 48 along the first set
42 of coil sections 31-35, and then along the second leg 50 along
the second set 44 of coil sections 36-40. Heat is transferred from
air flowing along first leg 48 of the air flow path to refrigerant
in the first set 42 of coil sections 31-35 such that the
refrigerant absorbs heat from the air and evaporates to lower the
temperature of the air below the dew point such that water vapor in
the air is condensed to liquid to dehumidify the air. The
refrigerant is circulated from the first set of coil sections to
the second set of coil sections by circulating refrigerant from a
coil section such as 31 of the first set 42 to the next serially
connected respective coil section such as 40 of the second set 44,
and then to coil section 32 of first set 42, and then to coil
section 39 of second set 44, and so on. Heat from the refrigerant
in the second set 44 of coil sections 36-40 is transferred to air
flowing along the second leg 50 of the air flow path, such that
heat is given up to the air and the refrigerant condenses, to raise
the temperature of the air such that dehumidified and warmed air
flows at 22 from the second leg 50 of the air flow path. Heat is
transferred from air flow along the first leg 48 of the air flow
path to air flow along the second leg 50 of the air flow path
through the media of the refrigerant, to put heat back into the air
flow along the second leg 50 from the air flow along the first leg
48, reducing the net cooling effect of coil 30, to reduce the net
load on compressor 12 by coil 30 such that compressor 12 will
consume power based on the net cooling load, while the coil
provides the greater cooling capacity of sections 31 through 35,
which allows more moisture to be condensed from the air with less
energy.
Air flow is directed from point 20 along the first leg 48 of the
air flow path by directing air flow across the first coil section
31 of the first set 42, then across second coil section 32 of first
set 42, and so on until air flow crosses the last coil section 35
of first set 42. Air flow is then directed along second leg 50 of
the air flow path by directing air flow across the last coil
section 36 of second set 44, and then across the next to last coil
section 37 of second set 44, and so on until air flow crosses the
first coil section 40 of second set 44. Air flow along the path 48,
50 from point 20 to point 22 is thus initially directed across
first coil section 31 of first set 42, and is lastly directed
across first coil section 40 of second set 44. It is preferred that
the coil inlet be the first coil section 31 of first set 42, though
the coil inlet may alternatively be the first coil section 40 of
second set 44. It is preferred that the coil outlet be the last
coil section 36 of second set 44, though an odd number of coil
sections may be used and the coil outlet may be the last coil
section of the first set.
In the embodiment in FIG. 2, the air flows through coil 30 from
point 20 to point 22 in a straight-through path, wherein the first
and second path legs 48 and 50 are rectilinearly aligned. The
refrigerant is circulated in a path having multiple parallel runs
31-40 interconnected at their ends by tubing, such as 46, such that
the outermost run 31 on one side of the coil is connected to the
outermost run 40 on the other side of the coil, and the next to
outermost run 32 on the one side of the coil is connected to the
next to outermost run 39 on the other side of the coil, and so on.
One of the outermost runs such as 31 is the coil inlet. A central
run such as 36 is the coil outlet. Air flow from point 20 is
directed along the first leg 48 of the air flow path along the
first portion 42 of the coil from outermost run 31 to central run
36, and the air flow is then directed along the second leg 50 of
the air flow path along the second portion 44 of the coil from
central run 36 to outermost run 40. The air flow path direction,
including along legs 48 and 50, is perpendicular to runs 31-40. The
restricted interconnecting tubing such as 46 provides a plurality
of expansion devices in the coil along the length thereof between
coil inlet 31 and coil outlet 36 progressively expanding the
refrigerant and progressively reducing refrigerant temperature. The
dehumidified air at point 22 is directed through condenser 14 to
provide warmed and dehumidified air at point 24.
FIG. 3 shows an alternate embodiment dehumidifier 58, and uses like
reference numerals from FIG. 2 where appropriate to facilitate
understanding. Instead of the straight-through air flow path of
FIG. 2, a loop-back air flow path is provided in FIG. 3. Coil 60 is
a serpentine member having multiple straight runs and having at the
end of each run a reverse bend leading to the next run. The coil
has a central dividing wall 62 extending perpendicularly to the
runs and dividing the coil into first and second portions 64 and
66. Air flow is directed in a loop-back path from point 68 to point
70 to point 22. The loop-back path has first and second legs 72 and
74. Air flow is directed leftwardly along first leg 72 along first
portion 64 of the coil in a leftward direction from the right end
of the coil to the left end of the coil to lower the temperature of
the air below the dew point such that water vapor in the air is
condensed to liquid to dehumidify the air. The air flow is then
reversed at U-shape bend 70 at duct 75 at the left end of the coil.
The air flow is then directed rightwardly along the second leg 74
of the air flow path along the second portion 66 of the coil in a
rightward direction from the left end of the coil to the right end
of the coil to raise the temperature of the air such that
dehumidified and warmed air flows from second leg 74 of the air
flow path at second coil portion 66 at the right end of the coil at
point 22.
Heat is transferred from air flowing along first leg 72 to
refrigerant in the first portion 64 of the coil. The refrigerant is
circulated to the second portion 66 of the coil and transfers heat
to air flowing along second leg 74 of the air flow path. Heat is
thus transferred from air flow along first leg 72 to air flow along
second leg 74 through the media of the refrigerant flowing through
coil 60 from coil inlet 76 to coil outlet 78. Heat is put back into
air flow along second leg 74 of the air flow path from first leg 72
of the air flow path, reducing the net energy requirements of coil
60, to reduce the net load on compressor 12 by coil 60 such that
compressor 12 may drive the left end of the coil at outlet 78 to
lower temperatures to cool more air below the dew point, without
increased energy consumption by compressor 12. The air flow path,
including first and second legs 72 and 74 and U-shape bend 70, and
each run of coil 60 are all coplanar. The leftward air flow along
leg 72 and the rightward air flow along leg 74 are parallel to each
other and perpendicular to each of the coil runs. The dehumidified
air at 22 is directed through condenser 14 to provide warmed and
dehumidified air at point 24. A plurality of expansion devices in
coil 60 along the length thereof between coil inlet 76 and coil
outlet 78 progressively expand the refrigerant and progressively
reduce refrigerant temperature and pressure. These expansion
devices are provided by the size of the tubing for the coil runs
and/or the reverse bends at the ends of the runs, and/or
restrictors such as 80.
In one implementation, air flowing into the coil at 20 in FIG. 2,
and at 68 in FIG. 3, had a temperature of 80.degree. F. The air at
the coil outlet 36 in FIG. 2, and 78 in FIG. 3, had a temperature
of 50.degree. F. The air leaving the coil at 22 had a temperature
of 65.degree. F. The refrigerant temperature entering the coil at
inlet 31 in FIG. 2, and at inlet 76 in FIG. 3, had a temperature of
70.degree. F., and the refrigerant leaving the coil at outlet 36 in
FIG. 2, and at outlet 78 in FIG. 3, had a temperature of 45.degree.
F. The refrigerant entering the coil at inlet 31 in FIG. 2, and at
76 in FIG. 3, was about 90% liquid and about 10% gas. The
refrigerant leaving the coil at outlet 36 in FIG. 2, and at 78 in
FIG. 3, was about 100% gas. The refrigerant in the first coil
section from point 31a to point 31b in FIG. 2, and from point 82 to
84 in FIG. 3, changed from 90% liquid and 10% gas to 88% liquid and
12% gas. The refrigerant in the first coil section 40 of the second
set 44 from point 40a to point 40b in FIG. 2, and from point 84 to
point 86 in FIG. 3, changed from 88% liquid and 12% gas to 89%
liquid and 11% gas. Thus, in coil section 31 in FIG. 2, and 76 in
FIG. 3, the refrigerant evaporates to lesser liquid and more gas,
and then in coil section 40 in FIG. 2, and the coil section between
points 84 and 86 in FIG. 3, the refrigerant condenses, but by a
lesser amount. This evaporation followed by lesser condensation
continues such that the coil 30 in FIG. 2, and 60 in FIG. 3, has a
net evaporator effect, with the refrigerant at the coil outlet
being 100% gas. The first portion 42 of coil 30 provided by coil
sections 31-35 in air flow path leg 48 functions as an evaporator,
while the second portion 44 of coil 30 provided by coil sections
36-40 in air flow path leg 50 functions as a condenser. Likewise in
FIG. 3, coil portion 64 in air flow path leg 72 functions as an
evaporator, and coil portion 66 in air flow path leg 74 functions
as a condenser.
The arrangements shown in FIGS. 2 and 3 provided dehumidification
of 5.1 pints of water per kilowatt hour of electricity, which is a
significant improvement over the 2 to 3.5 pints per kilowatt hour
encountered in prior art dehumidifiers of the form in FIG. 1. This
improvement in efficiency is enabled by reducing the net cooling
effect of coil 30, to reduce the net load on compressor 12 by coil
30 such that compressor 12 will consume power based on the net
cooling load, while the coil provides the greater cooling capacity
of sections 31-35, which allows more moisture to be condensed from
the air with less energy.
In the above noted implementation, the evaporating portion 42 of
coil 30 in FIG. 2, and evaporating portion 64 in FIG. 3, took about
10,000 BTUs of sensible and latent heat out of the air flow along
the first leg 48 in FIG. 2, and 72 in FIG. 3, and condensing
portion 44 of coil 30 in FIG. 2, and condensing portion 66 in FIG.
3, put back about 3,500 BTUs of heat into the air flow along leg 50
in FIG. 2, and 74 in FIG. 3. The compressor sees a net load of
6,500 BTUs, however 10,000 BTUs of heat is being absorbed from the
air in the evaporator portion of the coil to cool more air below
the dew point than otherwise possible if only 6,500 BTUs of heat
were removed from the air.
The coil presents a net cooling load on the compressor represented
by the enthalpy difference in air entering and leaving the coil.
Air entering the coil is cooled down below the dew point such that
water vapor in the air is condensed to liquid to dehumidify the
air. The air flow is then directed through the coil to heat the air
to a temperature below the incoming air to the coil and above the
dew point of the air. The air entering the coil is thus cooled down
below the dew point and then reheated before leaving the coil, such
that the air leaving the coil has a lower temperature than the air
entering the coil, and such that the air leaving the coil is
dehumidified relative to the air entering the coil. Air flow is
directed along a first set of coil sections, 42 in FIG. 2, and 64
in FIG. 3, giving up heat to refrigerant in the first set of coil
sections to evaporate refrigerant in the first set of coil
sections. The air flow is then directed along a second set of coil
sections, 44 in FIG. 2, and 66 in FIG. 3, absorbing heat from
refrigerant in the second set of coil sections to condense
refrigerant in the second set of coil sections. Refrigerant in the
coil is alternately evaporated and condensed differentially such
that less refrigerant is condensed in the condensing coil sections,
44 in FIG. 2, and 66 in FIG. 3, than is evaporated in the
evaporating coil sections, 42 in FIG. 2, and 64 in FIG. 3, such
that the coil outlet has a higher percentage gas refrigerant than
the coil inlet, and such that the coil outlet has a lower
percentage liquid refrigerant than said coil inlet, and such that
the coil outlet has a lower temperature than the coil inlet.
FIG. 4 shows an air conditioner and dehumidifier known in the prior
art air conditioning and dehumidifying for an enclosed space 100
such as the inside of a building 102, and uses like reference
numerals from FIG. 1 where appropriate to facilitate understanding.
Condenser 14 and compressor 12 are outside the building, and
expansion device 16 and evaporator 18 are inside the building. The
air flow at 22 from evaporator coil 18 cools the inside of the
building. Condenser 14 is outside the building and exterior to
space 100 and exhausts heat given up by the refrigerant during
condensing thereof. The heat is given up to air flow from point 104
to point 106.
FIG. 5 shows an air conditioner and dehumidifier in accordance with
the invention, and uses like reference numerals from FIGS. 2 and 4
where appropriate to facilitate understanding. Coil 30 is within
space 100 for cooling the space.
FIG. 6 shows an alternate embodiment of an air conditioner and
dehumidifier in accordance with the invention, and uses like
reference numerals from FIGS. 3 and 4 where appropriate to
facilitate understanding. Coil 60 is within space 100 for cooling
such space.
FIG. 7 shows a refrigeration cycle 110 known in the prior art as
provided by dehumidifier 10 in FIG. 1. The refrigerant is
compressed at portion 112 of the cycle, condensed at portion 114,
expanded at portion 116, and evaporated at portion 118.
FIG. 8 is a pressure-enthalpy diagram as in FIG. 7, but showing the
refrigeration cycle 120 in accordance with the present invention
provided by dehumidifier 18, FIG. 2, and 58, FIG. 3. The
refrigerant is compressed at portion 122 of the cycle, condensed at
portion 124, expanded at portion 126, and evaporated at portion
128. Portion 128 includes evaporating segments 130, FIG. 9, and
condensing segments 132. Evaporating segments 130 are provided by
coil sections 31 through 35 in FIG. 2 providing the noted first
coil portion 42. Condensing segments 132 are provided by coil
sections 36 through 40 providing the noted second coil portion 44.
In FIG. 3, evaporating segments 130 are provided by the coil
sections in first coil portion 64, and condensing segments 132 are
provided by the coil sections in second coil portion 66.
FIG. 9 does not show pressure drops induced by restrictions other
than the restriction of the coil tubing itself. If restrictions are
provided, they can be placed anywhere in the coil. In FIG. 2,
restrictions such as 46 are placed at the end of the condensing
runs for maximum efficiency, and the resulting pressure drops
.DELTA.P are shown at 134 in FIG. 10. In FIG. 3, the restrictions
such as 80 are placed in the middle of the evaporating or
condensing sections and provide pressure drops .DELTA.P as shown at
136 in FIG. 11.
It is recognized that various equivalents, alternatives and
modifications are possible within the scope of the appended
claims.
* * * * *